Synchronizer switching device



2 Sheets-Sheet l INVENTOR. I

S. MENDELSOHN ,SYNCHRONIZER SWITCHING DEVICE Filed April 21, 1939 Nov. 18, 1941.

' NOV. 18, 1941. s, MENDELsbHN 2,263,045

SYNCHRONIZER SWITCHING DEVICE Filed April 21, 1939 2 Sheets-Sheet '2 "WI lnlllllllllllllllrlllililm ATTORNEY.

Patented Nov. 18, 1941 UNITED STATE s PATENT OFFICE synonaomzan swrronmo DEVICE Samuel Mendelsohn, nmeuyn, N. r. Application April 21, 1939, Serial No. 269,115

2 Claims.

duced by ignition of a photoflash lamp. This is of extreme importance in the art of photography in order to obtain best results and especially in newspaper photography where it is frequently impossible for retakes.

In all synchronizing apparatus as employed with cameras of the focal plane shutter curtain type, of which I am aware, such apparatus has been subject to the disadvantageous feature that the shutter curtain' must be rewound prior to insertion of th photoflash lamp, otherwise the lamp is inadvertently ignited without the camera being focused or the shutter curtain being properly opened. This accordingly requires the photographer, after having taken one exposure to first rewind the focal plane shutter curtain and then insert the photoflash lamp in its socket.

Since this consumes an appreciable length of time it frequently happens that a photographer in his zeal to take a second exposure whenever possible, forgets the sequence of operation which results in the wasteful ignition of a photonash lamp and loss of opportunity for a second exposure. 1

It is accordingly an object of the present invention to provide a synchronizing mechanism for cameras of the focal plane shutter curtain type wherein the photoflash lamp can be ignited only when th focal plane shutter curtain is moving in an exposure taking direction.

Another object of the present invention is the provision of a synchronizing apparatus for cameras of the focal plane shutter curtain type wherein ignition of the photoflas h lamp is prevented during setting of the focal plane shutter curtain preparatory to an exposure.

Another object of the present invention is the provision of a synchronizing apparatus which can be readily attached humans of the focal. plane shutter curtain type, set for various exposure periods in order to insure complete opening of the shutter simultaneously with the moment of peak intensity of a photofiaah lamp. and wherein ignition of the photoflash lamp is prevented except during movement of the shutter curtain in an exposure taking direction.

Still further objects of the present invention will become obvious to those skilled in the art by reference to the accompanying drawings, wherein:

Fig. 1 is a perspective view of a camera of the focal plane shutter curtain type showing a synchronizing mechanism constructed in accordance with the present invention attached thereto.'

Fig. 2 is a fragmentary elevational view on an enlarged scale of the camera, as shown in Fig. 1,

and showing a side view of the synchronizing mechanism of the present invention;

Fig. 3 is a fragmentary elevational view on an enlarged scale of the camera as shown in Fig. 1 and showing the front of the synchronizing mechanism of the present invention with the cover removed and looking in the direction indicated by the arrows III-III of Fig. 2;

. Fig. 4 is a sectional viewon an enlarged scale, and taken on the line IV-IV of Fig. 3, of the synchronizing mechanisms of the present invention.

Fig. 5 is a fragmentary sectional view of the synchronizing mechanism as shown in Fig. 4 and showing one position of'the mechanism during operation;

Fig. 6 is a further fragmentary sectional view of the synchronizing mechanism as shown in Fig. 4 and showing another position of such mechanism during its operation, and

' circuit by which the synchronizing mechanism Fig. 7 is a schematic diagram of the electrical of the present invention causes ignition of the photofiash lamp.

Referring now to the drawings in detail a camera 5 of the focal plane shutter curtain type is shown in Fig. 1 to which the synchronizing mechanism of the present invention is attached. Such mechanism comprises a battery case B which is secured by a suitable bracket or the like (not shown) to the side of the camera. Disposed interiorly of the case are a pair of dry cell batteries I (Fig. 'l) which serve as the source of electrical energy for a photoilash lamp 8 upon closure of a switch I (Figs. 4 and 7) housed within a housing or cover plate III, as shown in the remaining figures of the drawings.

The camera}, as above mentioned, is of the focal plane shutter curtain type in which the shutter curtain is provided'with several succes- 'slve openings of different widths. As is well known in the art such camera is so constructed that during exposure. one of these openings flashes ac'rossthe film simultaneously with movement of a mirror ortheiike admitting the light and enabling registrationof the image on the film. Preparatory to an exposure the shutter curtain is wound by means of a knob l2 connected to the shaft to which the focal plane shutter curtain is secured.

In winding the shutter curtain a spring is tensioned to various degrees for, selecting the desired width opening which at a given period of time aligns with the focal plane and lens, thus enabling a comparatively large number of speed 7 I the present invention and its construction and operation is well known in the art, a detailed description thereof is believed unnecessary except in so far as required to adequately describe the presentinvention. It should suffice to say that the shutter curtain'is wound by the knob I! with attendant tensioning of the usual spring.

The shutter curtain trip mechanism, which is set or "cocked by movement .of a lever I3, is carried on the rear surface of a plate l4, the latter of which is secured to the side ofthe camera as can be seen in Fig. 1. I By reference more particularly to Figs. 2 to 6 inclusive, it will be seen that the knob i2 is secured to a short shaft l5 extending through the 4 plate i4 and on the rear surface of. the latter a gear wheel I5 is secured to this shaft l5 which l9, as can be seen in the several figures, are also rotated, but since these are'part of the tripping mechanism and among other functions of their gear wheel meshes with a small gear or pinion I! vided with a pivoted arm 5| adjacent tothe slot 55, which arm is provided with slots having graduations 54 corresponding to the same periods of time to which the tripping mechanism is set,

as shown at 25, the synchronizing mechanism is medium of the fastening screw 5'! and metallicwasher 55 and the spring contact terminal 55 is connected to a conductor 55. As shown in Figs.

2 and 3, in order to facilitate replacement or repair of the synchronizing mechanism it may be completely detached from the camera. For this purpose the conductor extends through'a short section of flexible armored cable 45 which issuitably fastened to'the plate 22 as by soldering or the like to form a mechanical and electrical bond, and at the top of the camera this armored armored cable and to which the conductor a is,

also connected so that a two conductor cable-44 may complete the connection to the batteries 1 and photoflash lamp 5.

To cause closure of the spring contact terminals and "of the switch 5, the shaft II is operation indicate the time period of exposure, 7

as shown at- 25 in Fig. 3, a detailed thereof is unnecessary.

The synchronizing. mechanism forming the description subject matter of the present invention and whicl is connected to the batteries 1 and photoplate l4. 'Projecting upwardly from this plate 22 is an annular collar 24 having an internal diameter slightly larger than and surrounding a flash lamp 8, as shown in Fig. '1, comprises'a plate 22 secured by set screwsor the like 25, to the hub integral with the plate for the shaft l5.

Surrounding this collar 24 for limited rotary movement thereabout. is another plate 25. The plate 25 is excentrically journaled about the collar 24 (see Fig. 3) to provide a slotted arm for the purpose of adjustment as will be described.

In order to hold plate 25 in a selected position about the collar. 24 and in frictional'engagement with the plate 22, an arcuate slot 25 is provided in the plate 25. Extending upwardly from the plate 22 and through the slot 25 is a post 21 which is provided with a coil spring 25 tensioned between a washer 29 and the cover plate I of As shown in Fig. 2 the cover plate I! is provisions to. the contrary.

provided with a collar 45-rigidly secured thereto as by a set screw 45 and having a pair of radially projecting pins 41 spaced 180 apart and so dis-' posed as to engage switch actuating means upon a rotation of the shaft [5. Since these-pins must pass the-contact terminals when the focal plane- For the purpose of preventing an engagement of the contacts in the shutter curtain winding direction while at the same time causingengase-v I ment of said contacts in the exposure moving direction of the shutter curtain, a spring member 45 is provided having one end secured in place ,7 adjacent the spring contact terminal 55. As. shown in Fig. 4 this spring member 45 is normally disposed for the greater portion of its length in parallel relation to the contact terminal 55 and having its free end 45 inclined and provided with an offset lip 45' disposed in the path of movement of pins 41. In the. exposure taking position of the camera with the shutter curtain wound to the preselected tension, the pin 41, together with the contact terminals 55 and 55 and the contact member 45, will be in the positionshown in Fig. 4.

Upon tripping of the lever n, the tripping, mechanism is'set in motion causing rotation of, Y

the shaft (5 together with the rigidly connected collar 45. The pin 41 carried by the collar accordingly strikes the-spring -contact member 45 duringits rotation in the direction indicated by .the arrow in Fig. 4 which forces the member 45 downwardly carrying with it the spring contact terminal 55. Thus the terminals 55 and 55 enabsence of a Proaaeaos of the circuit and attendant ignition of the photoflash lamp.

Since there is an appreciable time lapse before the desired width slot in the shutter curtain aligns with thelens such time lag is compensated for by adjustment of the tripping mechanism. At the same time there is a time lag between initial energization of the photoflash lamp and the moment of peak intensity which must synchronize with complete alignment of the desired width slot and lens for best results. To properly synchronize these two, the arm 32 is set as before mentioned to the same graduation (Fig. 2) on the pivoted arm 3| as that shown at 20 (Fig. 3) on the camera plate l4 Movement of the arm 32 thus rotates the plate 25 shifting the contact terminals 35 and 36 as well as the member 48 to thus vary the distance which the pins 41 must travel before causing closure of the contact terminals.

Following one exposure the photographer may immediately replace his photoflash lamp III and rewind the shutter curtain without danger of inadvertently igniting the lamp. This is due to the fact that as the shaft I 5 is rotated by the knob I2 the pins 41 move in the direction indicated by the arrow in Fig. 6. During their movement they will contact the underside of the lip 49' on the inclined terminal 49 of member 48 and lift it, as shown in Fig. 6, and as rotation of the pin 41 continues it will ride of! of the lip without causing closure of the contact terminals 35 and 36 even when the engagement of the pin 41 with the member 48 is broken, since the tension of the spring contact 85 is sufllcient to resist movement upon impact'by the member 48 when the latter is released from engagement with pin 41.

It will thus become obvious to those skilled in the art that a synchronizing mechanism is herein provided which is particularly applicable to cameras of the focal plane shutter curtain type. Moreover, such synchronizing mechanism is readily adjustable so as to condition the machanism in accurate synchronism with any preselected width opening of the shutter curtain. The synchronizing mechanism is also so constructed as to preclude ignition of a photoflash lamp except during exposure moving direction of the shutter curtain thus eliminating the disadvam tageous feature of inadvertently igniting and wasting a photoflash lamp prior to proper focus.

Although .one specific embodiment of the present invention has been shown and described it k to be understood that other modifications may be made without departing from the spirit and scope of the appended claims.

What is claimed is: Y

1. A synchronizing mechanism for cameras of the focal plane shutter curtain type having various width openings therein comprising a shaft for winding and tensioning said shutter'curtain to various degrees preparatory to an exposure and to regulate the speed of movement of said shutter curtain to align a preselected width opening with the focal plane after the lapse of a predetermined period of time, tripping mechanism for releasing said shutter curtain and causing rotation of said shaft, a photoflash lamp adapted to be connected to a source of electrical energy to cause ignition thereof, an electric switch provided with a flexible actuator disposed adjacent said shaft and operable during the exposure direction movement of said shutter curtain to connect said photofiash lamp to said source, and a member rotatable with said shaft and engageable with the flexible actuator of said switch in the exposure direction movement of said shutter curtain to cause closure of said switch and also engageable with the flexible actuator of said switch during winding and tensioning of said shutter curtain to avoid closure of said switch and the inadvertent ignition of said photoflash lamp.

2. A synchronizing mechanism for cameras of the-focal plane shutter curtain type having various width openings therein comprising a shaft for winding and tensioning said shutter curtain to various degrees preparatory to an exposure and to regulate the speed of movement of said shutter curtain to align a preselected width opening with the focal plane after the lapse of a predetermined period of time, tripping mechanism for releasing said shutter curtain and causing rotation of said shaft, a photoflash lamp adapted to be connected to a source of electrical energy to cause ignition thereof, an electric switch provided with a flexible actuator disposed adjacent said shaft and operable during the exposure direction movement of said shutter curtain to connect said photoiiash lamp to said source, a member rotatable with said shaft and engageable with the flexible actuator of said switch in the exposure direction movement of said shutter curtain to cause closure of said switch and also engageable with the flexible actuator of said switch during winding and tensioning or said shutter curtain to avoid closure of said switch and the inadvertent ignition of said photoilash lamp, and

a supporting plate for said switch adjacent said shaft and axially adjustable thereabout to vary the distance said rotatable member travels before engaging the actuator of said switch in order to synchronize the moment of peak intensity from said photoflash lamp with alignment of the preselected width opening and said focal plane.

SAMUEL MENDELBOHN. 

